Wave damper device



Aug. I7-, 1965 J. c. KREPAK WAVE DAMPER DEVICE Filed Oct. 19, 1961 Q QIP w r NN N NQ N m .c H n n n/Dw\ NMR NN m W. M Q, n Nf/ Nm N /NN N\NN/x WM 4m f a l (E u .wll NN auf xi nfl In. H Q im DVNMWMW al 1MM@ A mmY NN n n w mw @DNN m M N "J n D H l n E NA\ n vm.

llllllllllllll IIQ llllllllllllllllllllll Il Inl- 3,200,598 WAVE DAMPERDEVICE John C. Krepalr, 315 Sklar Bldg., Shreveport, La. Filed Oct. 19,1961, Ser. No. 146,103 4 Ciairns. (Cl. 61--5) This invention relates toa wave damper and more particularly to a wave damper designed to reducethe size and force of Waves and swells caused by high winds, storms, andhurricanes originating ott shore.

The primary object of the invention is a wave damper designed to protectott shore installations and moorings from the pressure of large wavesand swells driven by heavy winds. v

' A further object of the invention is a wave damper of relativelysimple construction which may be assemin any desired location.

' Another object of the invention is a wave damper simple in design,eicient in operation, and lower in manufacturing cost than other similartype devices.

Further objects and advantages of the present invention will becomereadily apparent by referring to the following detailed description whentaken with the accompanying drawings wherein:

FIGURE l is a perspective view illustrating the wave damper constructedin accordance with the teachings of the present invention.

FIGURE 2 is a plan view of the wave damper shown in FIG. 1 illustratingthe manner of installation and in dotted lines the area of relative calmeffected by such installations.

FIGURE 3 is an enlarged cross-sectional view of the mat forming part ofthe present invention illustrating the manner in which a plurality ofair cells are` formed in said mat.

FIGURE 4 is a perspective view of the wave damper illustrated in FIG. 1and showing a slightly modified form f construction.

FIGURE 5 is a plan View of the wave damper illustrating an alternatemanner of installation.

FIGURE 6 is a plan View of the wave damper illustrating still anothermanner of installation.

Referring to FIG. 1, the wave damper 1@ of the present invention isshown as comprising a substantially rectangular top mat 11. The top mat11 can be constructed of a plastic material or other imperviousmaterial. The top mat is buoyantly supported on the surface of the bodyof water 12 and is provided with a plurality of air cells, thecon-struction of which will be later described.

One of the longitudinal edges of the rectangular Sheet 11 is disposedWindward and is submerged below the surface of the Water 12. The edge isheld in a submerged position by a plurality of cables 13 secured to aplurality ot anchors 14 on the bottom 15 of the body of water 12. Theopposing longitudinal edge of the top mat 11 is also submerged below thesurface of the Water 12 by a plurality of cables 16 secured to aplurality of anchors 17. The sides of the top mat 11 are similarlypositioned by cables 18 and corresponding anchors 19.

interposed between the anchors 14, 17, 19 and the top mat 11 in asubmerged position on the cables 13, 16, 18 are shock absorbers 2t)comprised of springs 21 and safety cables 22. Positioned immediatelyabove the shock absorbers 20 are buoyant iioats 23.

Spaced in descending relationship -t-o the top mat 11 are a plurality ofsecondary rectangular buoyant mats 24. The mats 24 are Secured alongtheir respective Windward longitudinal edges to the cables 13 above theshock absorbers 20. The remaining edges of the secondary mats 24 areleft to oat free under the top mat 11 and will, because of theirbuoyancy, lie directly under the top mat 11 under normal conditions.

United States Patent O As seen in FIG. 3, the mats 11, 24 areconstructed in a manner which provides a plurality of air cells 25providing the mats 11, 24l with substantial buoyancy. Flexible one-wayplastic check valves 36 are installed at intervals through mats 11, 24to allow air or trapped gases as at arrow A to escape from under mats11, 24. As shown, the plane surface 26 of the mats has secured thereovera second sheet 27 of like material which may be plastic or other.suitable impervious material which is secured to the surface 26 atspaced points by heat sealing or other means.

A slightly modified form of the wave damper is shown in FIG. 4. In thisinstance, the wave damper as illustrated in FIGS. l and 2 is furtherprovided with a plurality of elongated members 28 pivotally mounted oncable 29 suspended between floats 30 positioned by cables 31 secured toanchors 32. The elongated members 28 cxtend horizontally over the mat 11and have their free ends in contact therewith.

The detailed manner of installation of the wave damper is shown in FIG.2. As illustrated, the mats 11, 24 are positioned so that the longdimension will meet the waves coming in the direction of the windillustrated by the arrow W. On the lee side of the wave damper iscreated an area of relative calm, indicated by dotted lines AB, in whichthere is provided an anchorage 33 to which vessels 34 may be secured.This area is illustrated as substantially triangular in configuration.

By referring to FIGS. 1 and 2, the effect of the wave damper on heavyseas and swells will become apparent. As the waves approach the damper1t), they rst come in contact with the submerged leading edges of thesecondary mats 24. A portion of the descending energy in the wave isforced to transmit its energy between the top mat 11 and the secondarymats 24. A portion of the descending wave breaks over the edge of thetop mat 11 and depresses it momentarily. As 4the top mat 11 comes to thesurface, it pushes this part of the wave back in the direction of theoncoming waves.

Where the modied installation of FIG. 4 is used the elongated members 28help break up the descending wave by interrupting the smooth transfer ofenergy and throwing the waves out of harmony. The energy of the Waterjust below the surface and passing under the top mat 11 is dampened bythe pressure exerted by the atmosphere pushing down on the top mat 11and by the weight of the water held against the underside ofthe top mat11 by the atmospheric pressure bearing down on the surface of the watersurrounding the mat 11 and by the buoyancy of the secondary mats 24pushing up. The eX- tent of the pressure exerted by the atmosphere onthe top mat 11 and by the weight of the water held against the undersideof the top mat 11 and by the buoyancy of the secondary mats 24 is greatenough whereby the energy in a single wave is not suiiicient to transmitits energy to the lee side thereof. By providing a wave damper such asthat disclosed herein it will be readily seen that the energy ofmovement of the water in waves on the surface of the water as well asthe energy of movement of the water just below the surface is readilydissipated, providing an area of safe, calm, relatively undisturbedwater on the lee side of the top mat 11 whereby a safe anchorage forvessels can be provided as well as an area of relative calm in whichoffshore st ructures may be constructed.

FIGS. 5 and 6 illustrate alternate methods of positioning the wavedamper 10 around an anchorage 33 for vessels 34 to provide asubstantially greater area of calm than was created by the installationof FIG. 2. FIG. 5 shows a substantially circular arrangement of thedamper 10 with overlapping ends to provide an entrance as at 35. FIG. 6shows a substantially rectangular arrange- 3 ment of the mats 11 withentrances for the vessels 34 being provided as at 35.

In either of the configurations shown in FIGS. 5 and 6, the formdisclosed in FIG. l or the modification shown in FIG. 4 may be used.

While the invention has been described in its preferred embodiments, itwill become apparent to those skilled in the art that there aremodifications and variations thereof. Such modifications and variationsare considered to be Within the scope and Spirit of the appended claims.

I claim:

1. A wave damper for a body of water comprising a first buoyantimpervious sheet on the surface of the water, a plurality of secondaryimpervious buoyant sheets disposed in underlying relation to said firstbuoyant sheet, cable means anchoring opposed submerged elongated edgeportions of said first sheet to the bottom of the body of water, theremaining area of said first sheet floating on the surface of the water,opposed elongated edge portions of said secondary sheets being submergedand secured below the surface ofrthe water, the remaining area of saidsecondary sheets extending under said cable means and floating near thesurface of the water under said first sheet, said secondary sheetsincluding a plurality of elongated parallel spaced members disposedhorizontally over said first sheet, supporting means carrying one end`of each elongated member, the other end vof each elongated member beingfree and in contact with said first sheet.

, 2. A wave damper as defined in claim 1 wherein said supporting meansincludes a first cable pivotally connecting said elongated members inspaced relationship, a fioat disposed at each end of said cable, andsecond anchored cables secured to each of said oats.

3. A wave damper comprising a rst buoyant rectangular mat including aplurality of aircells supported on the surface of a body of water, oneedge of said sheet being disposed to Windward, a first plurality ofcables secured to said one edge, spring shock absorbers in each cable,anchors secured to each cable, said anchors holding said one edge insubmerged position, a further plurality of cables secured to theopposite edge of said mat, spring shock absorbers in said furtherplurality of cables, anchors secured to eac'h of said last-mentionedcables, said last-mentioned anchors holding said opposite edge insubmerged position, a plurality of secondary rectangular buoyant mats ofsubstantially the same width as said first mat and being secured Valongone of their edges in spaced descending relation to said first-mentionedplurality of cables above the shock absorbers thereon and extendingunder said first'mentioned plurality of cables, said secondary matshaving their opposite edge free to fioat upwardly into contact with theundersurface of said first buoyant mat andv flexible one-way checkvalves installed at Vspaced intervals in each of said mats.

4. A wave damper comprising a firstbuoyant rectangular mat includingaplurali'ty: of air cells supported on the surface of a body Yof water,one edge of said sheet being disposed to Windward, a first plurality ofcables secured to said one edge, spring shock absorbers in each cable,anchors secured to each cable, said anchors holding said one edge insubmerged position, a further plurality of cablessecured to the oppositeedge of said mat, spring shock absorbers in said furtherY plurality ofcables, anchors secured to each of said'last-'rnentioned cables, saidlast-mentioned anchors holding said opposite edge in submerged position,a plurality of secondary rectangular buoyant mats of substantially thesame width as said first-mentioned mat andr being secured along one oftheir edges in spaced descending relation to said firstmentionedplurality of cables above the shock absorbers thereon and extendingunder 'said firsbmentioned plurality of cables, said secondary matshaving their opposite edge tree to fioat upwardly into Contact with theundersurface of said first buoyant mat, flexible one-Way check valvesinstalled at spacedrintervals in each of said mats, a pair of additionalanchors spaced from said first-mentioned anchors, cables secured to saidadditional anchors and extending outwardly and vdownwardly with respectto said one edge of said first mat, a transverse cable secured betweenthe tops of said last-mentioned cables, fioats secured to saidtransverse cable, and a plurality of elongated members secured to saidtransverse cable in spaced'relationship and extending horizontally oversaid first mat and having free ends in contact therewith.

vReferences Cited bythe Examiner UNITED STATES PATENTS EARL I. WITMER,Primary Examiner.

VJILLIAM I. MUSHAKE, JACOB SHAPIRO, JACOB L. NACKENOFF, Examiners.

1. A WAVE DAMPER FOR A BODY OF WATER COMPRISING A FIRST BUOYANTIMPERVIOUS SHEET ON THE SURFACE OF THE WATER, A PLURALITY OF SECONDARYIMPERVIOUS BUOYANT SHEETS DISPOSED IN UNDERLYING RELATION TO SAID FIRSTBUOYANT SHEET, CABLE MEANS ANCHORING OPPOSED SUBMERGED ELONGATED EDGEPORTIONS OF SAID FIRST SHEET TO THE BOTTOM OF THE BODY OF WATER, ANDREMAINING AREA OF SAID FIRST SHEET FLOATING ON THE SURFACE OF THE WATER,OPPOSED ELONGATED EDGE PORTIONS OF SAID SECONDARY SHEETS BEING SUBMERGEDAND SECURED BELOW THE SURFACE OF THE WATER, THE REMAINING AREA OF SAIDSECONDARY SHEETS EXTENDING UNDER SAID CABLE MEANS AND FLOATING NEAR THESURFACE OF THE WATER UNDER SAID FIRST SHEET, SAID SECONDARY SHEETSINCLUDING A PLURALITY